Borehole reamer-stabilizer with improved fluid circulation

ABSTRACT

A plurality of passages transmit fluid end to end in the reamerstabilizer body. Individual cutters are mounted on hollow shafts affixed to the reamer-stabilizer body. A circular passage transmits fluid to the center of the hollow shafts. Holes connect the outside of each shaft with the hollow central portion. Spiral grooves are located longitudinally on the inside diameter of the cutter.

I United States Patent 1151 Dysart 1 1 May 2, 1972 [541 BOREHOLE REAMER-STABILIZER 2,915,291 12/1959 0111161: ..175/34s WITH IMPROVED FLUID 3,109,501 11/1963 Pugh ....175/325 3,268,018 8/1966 Neilson 175/337 X CIRCULATION 3,303,900 2/1967 Kloesel et a1. ....l75/339 [72] Inventor: Theodore R- Dysar Dal Te 3,400,773 9/1968 Tiraspolsky et al.. 1 75/325 [73] Assign: Dresser Industries, Inc" Dallas, Tex. 3,494,432 2/1970 Garrett ..175/339 [22] Filed: Dec. 28, 1970 Primary Examiner-David H. Brown Anarney-Robert W. Mayer, Thomas P. Hubbard, Jr., [21] Appl 101696 Raymond T. Majesko, William E. Johnson, Jr. and Eddie E.

Scott [52] 0.8. CI ..l75/325, 175/337, 175/345 [51] Int. Cl. ..E21b 9/08, E2lb 9/24, E2lc 23/00 [57] ABSTRACT [58] Field k A plurality of passages transmit fluid end to end in the reamerstabilizer body. Individual cutters are mounted on hollow shafts affixed to the reamer-stabilizer body. A circular passage [56] Rem-mm Cited transmits fluid to the center of the hollow shafts. Holes con- UNITED STATES PATENTS nect the outside of each shaft with the hollow central portion.

Spiral grooves are located longitudinally on the inside diame- 1,139,529 5/1915 Hughes 175 345 x mom mm 1,399,863 12/1921 Hughes ..l75/337 X 2,549,420 4/1951 Camp ..175/345 X 11 Claims, 4 Drawing Figures PATENTEDHAY 21812 3,659,663

SHEEY 10F 3 INVENTOR THE ODORE R. DYSART A TTORNE Y I PATENTEUMAY 2:972

SHEET 2 [IF 3 FIG. 4

INVENTOR THEODORE R. DYSART ATTORNEY PATENTEDHM 2 1972- SHEET 3 BF 3 I l l I NVENTOR THEODORE R. DYSART FIG. 3

ATTORNEY BOREHOLE REAMER-STABILIZER WITH IMPROVED FLUID CIRCULATION BACKGROUND OF THE INVENTION The present invention relates to the art of earth boring and more particularly to a borehole reamer-stabilizer.

This type of device may be referred to as a bore control device. A multiplicity of rollers, generally three, are mounted longitudinally on an elongated reamer-stabilizer body. The reamer-stabilizer body is adapted to be connected as an element of a rotary drill string. Drilling fluid is circulated through the reamer-stabilizer body string a immediately of the fluid is bled off and directed to the space between the individual cutters and the shafts upon which they rotate.

The present invention may be used for blast hole drilling in mining. The reamer-stabilizer is included as an element in a rotary drill string and is positioned somewhere above the drill bit. Air is generally used as the drilling fluid in blast hole drilling.

The reamer-stabilizer must be sturdy and yet must not be unduly bulky or have a diameter greatly in excess of the diameter of the drill string. Fluid must be directed between the rollers and the shafts upon which they rotate. In addition, the reamer-stabilizer must transmit drilling fluid from the drill string element immediately above it to the drill string element immediately below it and must not impede fluid circulation.

DESCRIPTION OF THE PRIOR ART A bore control device is shown in US. Pat. No. 3,303,900 to J. A. Kloesel, Jr. et al. patented Feb. 14, 1957. A reamerstabilizer body is adapted for connection as an element in a drill string. A plurality of cutter-centralizer rollers are rotatably mounted around the outer periphery of the reamerstabilizer body. Air passage means are provided to bleed a portion of the pressurized air from the drill string and deliver it to the space between each roller and the shaft on which it rotates.

ln U.S. Pat. No. 3,494,432 to W. R. Garrett patented Feb. 10, 1970, a reamer-stabilizer is shown. The reamer-stabilizer consists of an upper body section and a lower body section. The upper and lower bodies are connected by a plurality of hollow, tubular members and rollers are mounted on said tubular members. Fluid circulates through said reamer-stabilizer by entering the upper body and continuing through the hollow shaft and continuing into the lower body portion.

Fluid circulation through the reamer-stabilizers of the prior art has proved to be somewhat of a problem. Some of the prior art reamer-stabilizers have not been strong enough to withstand the high torque loads imposed upon it during the drilling operation. Other prior art devices have impeded the circulation of drilling fluid through the drill string and difficulties have been encountered in transmitting the proper amount of fluid to the cutters.

SUMMARY OF THE INVENTION The present invention provides a reamer-stabilizer with improved fluid circulation. Fluid is transmitted through the reamer-stabilizer by a central passageway and additional passageways located in a plurality of support sections. A circular passageway transmits fluid to each of the roller shafts to provide fluid for cooling and purging purposes only.

Central fluid passages extend along a portion of the length of the roller shafts and holes from the outside of the roller shafts extend into the central passage. Spiral grooves are located in a longitudinal direction on the inside diameter of the cutters thereby providing improved fluid circulation in the bearing. The fluid circulation extends along the entire length of the cutter. The present invention provides free passage of circulating fluid through the reamer-stabilizer thus reducing the pressure loss burden on the system.

The cutters of the present invention include reaming capabilities in both the down and up direction in case of undergauged holes in the down direction or in the case of a caving hole when moving in the up direction. A wear bushing is provided on the lower portion of the body pocket to reduce abrasive wear. The individual cutters includea-stabilizing section in the center and reaming sections on either end. Stabilizing sections consist of a plurality of flattop carbides mounted flush with the cutter outer diameter and the reaming section includes carbides mounted so that they protrude from the cutter outer surfaces. 7

It is therefore an object of the present invention to provide an improved borehole reamer-stabilizer.

It is a further object of the present invention to provide reamer-stabilizer with improved fluid circulation.

It is a still further object of the present invention to provide a reamer-stabilizer that is stronger than those of the prior art.

It is a still further object of the present invention to provide a reamer-stabilizer with a longer life.

It is a still further object of the present invention to provide a stabilizer and a reamer.

It is a still further object of the present invention to provide a reamer-stabilizer which allows free air passage thereby reducing pressure loss through the device. 7

The above and other objects and advantages of the present invention will become apparent from a consideration of the following detailed description of the invention when taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a reamer-stabilizer constructed in accordance with the present invention.

FIG. 2 is a section taken along 2,2.

FIG. 3 is a partially cut away view of the reamer-stabilizer.

FIG. 4 illustrates another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 and 2, a reamer-stabilizer is indicated generally at 11. The stabilizer body 12 is adapted to be connected as an element of a drill string. The upper portion 13 of body 12 is threaded in order that it may be connected to an element of the drill string immediately above. The lower portion 14 includes internal threads that connect the drill string element immediately below.

Drilling fluid enters an upper central passageway 15, is transported through the'reamer-stabilizer and exits through a lower central passageway 16. A portion of the drilling fluid is transported from the upper central passageway section 15 to the lower central passageway 16 by middle central passageway 17. Three side passageways 18, 18', 18" transport other portions of the drilling fluid from upper passage 15 to lower passage 16.

Three roller cutters 19, 19' and 19" are positioned on the reamer-stabilizer body 12. The roller cutters are rotatably mounted on three individual shafts 20, 20' and 20". The shafts each include a central passageway 21, 21 and 21." and holes connect the central passages with the external portion of the shafts. A circular passage 22 allows fluid to be transmitted from side passages 18, 18' and 18" to the central passages 21, 21 and 21". This allows a portion of the drilling fluid to be diverted to the area between the shafts and the internal surface of the rollers for cooling and purging purposes. The exact amount of air required for efficient operation may be transmitted to the rollers. Also, a stronger stabilizer is provided because the rollers and the roller shafts may be smaller yet stronger. Consequently, the, entire reamer-stabilizer provides better performance.

Referring now to FIG. 3, the reamer-stabilizer is shown in greater detail. The reamer-stabilizer body 12 consists of an upper portion 23 and a lower portion 24. Upper portion 23 and lower portion 24 are connected by weld 25. A dowel pin 26 aligns the two portions during welding. Cutter 19 is shown mounted on shaft 20. Shaft 20 includes a central passage 21 that allows drilling fluid to be transmitted to the area between the cutter 19 and shaft 20. A series of holes 27, 27', 27" and 27" connect the central passage 21 with the area between cutter 19 and shaft 20. Flattened portions of the shaft 20 are provided around the drilling fluid exit holes. The angle between the shaft center line and these flattened transverse notches is shown to be 90 but it is understood that the angle could be less than 90. A number of spiral grooves 28, 29, 30, and 31 are provided in the internal surface of the roller cutter 19. Each of the grooves terminates in an exit hole such as exit hole 32 shown in roller cutter 19. The drilling fluid exits through holes 27, 27, 27" and 27". As roller cutter 19 rotates, the grooves 28, 29, 30, and 31 will alternately be positioned over one of the holes. This allows the drilling fluid to be circulated along the entire length of the roller cutter 19. The grooves 28, 29, 30, and 31 are shown at an angle to the center line of shaft 20; however, the grooves could be parallel, or nearly parallel, to the center line of shaft 20 and the holes in shaft 20 staggered.

Cutter 19 includes an upper portion 33 that is canted to provide a reaming action for use when the borehole is caving. The cutter 19 also includes a lower portion 34 that is canted to provide reaming action during drilling. The cutters may be provided with carbide inserts to facilitate disintegration of the formations.

Referring now to FIG. 4, another embodiment of the present invention is shown. A rolling cutter 35 is mounted on a shaft 36. Shaft 36 is positioned in the body of a reamer-stabilizer in the same manner as the previous embodiments. The drilling fluid enters central passage 37 of shaft 36 and exits through holes 38, 39, 40, and 41. A series of grooves 42, 43, 44, and 45.are milled in the outer surface of shaft 36. The drilling fluid is transported along the entire length of the cutter 35 by the series of grooves.

The present invention provides free passage of circulating fluids through the reamer-stabilizer thus reducing the pressure loss burden on the system. in addition, the reamer-stabilizer of the present invention can be made much stronger than those of the prior art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A device to be connected as an element of a rotary drill string comprising:

a main body portion that can be connected as an element of a drill string; at least one roller, rotatably mounted on said main body portion; and

fluid passage means for transporting a circulating fluid from one end of the device to the other end, said fluid passage means including a central passage located on the central axis of said main body portion and at least one side passage located in the main body portion and offset from the central axis of said main body portion.

2. The device of claim 1 including second fluid passage means for transmitting a circulating fluid to said at least one roller, said second fluid passage means in communication with said fluid passage means.

3. The device of claim 2 wherein said second fluid passage means includes at least one shaft mounting said at least one roller, said shaft having a tubular portion and holes extending into said tubular portion.

4. The device of claim3 wherein said tubular portion of said shaft extends along the entire length of the shaft.

5. The device of claim 3 including at least one groove on the external surface of said at least one shaft. 7

6. The device of claim 3 wherein said roller includes an annular, central opening and at least one groove on the internal surface of said central opening.

7. The device of claim 5 wherein said at least one groove extends at an oblique angle to the central axis of said roller.

8. The device of claim 6 wherein said at least one groove is a spiral groove.

9. In a bore control device having a body portion that can be connected as an element of a drill string with internal passage means for transfiorting circulating fluid from one end of the device to the 0 er end and at least one roller mounted on a shaft connected to the body portion, the improvement comprising:

passage means in said shaft, in communication with said internal passage means, for transporting circulating fluid to area between said roller and shaft; and at least one groove in the internal surface of said roller. 10. The device of claim 9 wherein said at least one groove extends at an oblique angle to the central axis of said roller.

11. The device of claim 10 wherein said at least one groove is a spiral groove. 

1. A device to be connected as an element of a rotary drill string comprising: a main body portion that can be connected as an element of a drill string; at least one roller, rotatably mounted on said main body portion; and fluid passage means for transporting a circulating fluid from one end of the device to the other end, said fluid passage means including a central passage located on the central axis of said mAin body portion and at least one side passage located in the main body portion and offset from the central axis of said main body portion.
 2. The device of claim 1 including second fluid passage means for transmitting a circulating fluid to said at least one roller, said second fluid passage means in communication with said fluid passage means.
 3. The device of claim 2 wherein said second fluid passage means includes at least one shaft mounting said at least one roller, said shaft having a tubular portion and holes extending into said tubular portion.
 4. The device of claim 3 wherein said tubular portion of said shaft extends along the entire length of the shaft.
 5. The device of claim 3 including at least one groove on the external surface of said at least one shaft..
 6. The device of claim 3 wherein said roller includes an annular, central opening and at least one groove on the internal surface of said central opening.
 7. The device of claim 5 wherein said at least one groove extends at an oblique angle to the central axis of said roller.
 8. The device of claim 6 wherein said at least one groove is a spiral groove.
 9. In a bore control device having a body portion that can be connected as an element of a drill string with internal passage means for transporting circulating fluid from one end of the device to the other end and at least one roller mounted on a shaft connected to the body portion, the improvement comprising: passage means in said shaft, in communication with said internal passage means, for transporting circulating fluid to area between said roller and shaft; and at least one groove in the internal surface of said roller.
 10. The device of claim 9 wherein said at least one groove extends at an oblique angle to the central axis of said roller.
 11. The device of claim 10 wherein said at least one groove is a spiral groove. 